Perception & Illusions: the Moon.

Shouldn't those be the same? An illusion is nothing more than a perception gone wrong. Maybe the most important part is that you will have to discover that your perception is wrong! Otherwise how would you know that what you saw (heard, et cetera) was an illusion?

Ever thought about the moon as an illusion?
No, don't get me wrong, I do not state that the moon is an illusion, no, it does exist, and we do see it, and it's there (at least, I believe it is, since personally I've never been there).
So how can the moon be an illusion?

When you look up at the sky, and there's a moon visible, you'll experience a yellow disc, far away. But if you see the moon somewhere at the horizon, you will see a larger disc. It still is far away, but it seems bigger. That could be the illusion?
In fact, it isn't. The illusions is when you see it up in the sky. At the horizon you see it in its full glory, full size, the real size. Up in the sky? Well, your brain knows that it is far away, very far away, and to experience that, and with no clues (as you have when you see it on the horizon) about its actual size, the brain makes it smaller than it really is.

So the illusion is not what you perceive. What you perceive is correct, there is a moon, and it's far, far away, unreachable for an average person. But, in order to perceive that, you brain delivers an illusion, a smaller moon.


for further explanation: http://science.nasa.gov/headlines/y2005/20jun_moonillusion.htm

Cultural Illusions

It was not my intention to write about illusions that much, but you know teachers, they love to explain. So illusions again, simply to answer the question what I consider to be cultural illusions.
Let me show you an example:

Of course, we all see a zebra, that is not the illusion. The question is what do you perceive from a zebra? Apparently most white people see a white animal with black stripes, whihttp://www2.blogger.com/img/gl.link.gifle most black africans see a black animal with white stripes.
I guess the next picture (from the University of Bergamo) is cultural free?

By the way, in search of information about the use of post-its for user testing I found a link to an article about its use for brainstorming, but also a link to a "proper zebra-crossing":
http://hiddenchemistry.com/proper-zebra-crossings/

I am not so very sure that foregoing example is a real cultural illusion, but the next is. Look at these stairs:

Again, the illusion is not whether these are stairs or not, but how do you perceive them. Are they going up? Or are they going down?
Apparently most Europeans and Americans perceive these stairs as 'going up', while people from countries where the direction for reading is from right to left look upon these stairs as going down.

It makes me wonder if the same goes for the next stairs:

Are these stairs going up or going down? Based upon what?

Let me finish with the most interesting stairs, several illusions appear together here:

If you want to know more about it, read the accompanying article: http://www.quantonics.com/Stairs_As_Perceived_by_Our_Quantum_Stages.html

Tunnel-vision

Tunnel-vision is a proces where clues seem to lead us in a certain direction, whereafter following information seems to justify our presumption.
The first time I heard about it, was concerning an investigation by the police, where the investigating officers jumped to a conclusion in the first stages of an ongoing investigation. Thereupon all clues that conflicted with their conclusion were ignored (to be "of no importance" of "inconclusive") while clues that reinforced their idea were accentuated.
And yes, an innocent men was sent to prison for over 10 years....
Recently I came across the same problem with two students working on their final project. In an early stage they had a good brainwave, got a good idea (and the idea still is), but in the following research they just looked at facts that supported their initial design, while ignoring conflicting facts. And that is just no the right way a research should be executed. (And right so, because in their subsequent research they did find reasons to alter their original design, so came up with a better product in the end!)
And now we, apparently we fall for the same trap. Consider the following pictures:



Do you see any parallel lines? In the upper picture it is evident, but what about the lower? No? Neither do I. Nevertheless the horizontal line are parallel, although you can't see so. (Don't believe me, check!)

This was first discovered during the redecoration of a pub in Bristol, the owner decided that he like black and white tile alternating on the outside of his pub. The tiles were to be set in stretching bond (each tile is placed with its center on top of the border between two tiles). When the decoration was finished, it didn't please the owner, of course, it was not what he intended. Nowadays the pub is famous all over the world because of its outside tiles.

For an explanation of the effect, read the article from Bristol.

Speaking of a tunnel


When you see the spirals, you realise that you can go deeper and deeper. Unfortunately you jumped to the conclusion that it are spirals that you see. I suggest you follow the cirkels with your finger to be absolutely sure. There really is no tunnel to go into. But at least now you know why it is called tunnel-vision!.

Illusions - I

Perception seems to be a key-item for me. When our mind plays tricks with us, we call that illusion. Several types of illusions do exist. We may encounter verbal illusions, visual illusions, cultural illusions (hmm, aren't they all, maybe I should look into that) a.s.o.

Illusions are as old as mankind. Wellknown examples as "Trompe d'oeil" (yes, there should be a link here, hmm, maybe when I find more time. For now just google yourself).


Very intriguing is what is called the "Hollow Face - illusion", several examples exist, which I will lead you to. Look at the accompanying picture, the little paper dragon. When you do not know what is the matter, you don't see anything unusual. Let's illustrate this with two movies:

1. The Hollow Face - illusion, face of Richard Gregory.

2. Charlie Chaplin - Hollow Face - illusion

This is all about assumption & perception. We know what we see, but our minds are unwilling to accept what it is that we see, so they create our own reality, and we are most happy with it. Try to stay happy when you look out your window and realise this is what we do every day.

For years I was very interested in virtual reality, only to find out, that reality already was quite virtual as it is. The same goes for 3-D objects. Some of us spend a lot of time creating them (not me, I'm just too lazy, although I did try some ray-tracing, years & years back). And always they are trying to create a type of reality that just waits to be rebuild in our heads.

Consider the next picture, especially tiles 'A' and 'B':


Myself, I was very intrigued by the fact that both surfaces have the same color. I mean, you don't SEE the same color! There are several ways to prove that they indeed have the same color. Use a colorpicker to check on the colors (I didn't want to believe it, so I did), or better view the movie:
http://web.mit.edu/persci/gaz/gaz-teaching/flash/plaid-movie.swf

Here, again, it is our assumption that creates the illusion, our minds 'enhance' the effect, by trying to create the picture that would be responsible for what we actually see. If those tiles look the same, than they should be a different color, because the upper one is in the light, while the lower surface is in the dark. If they're the same, they must be different!

We will encounter more of this in the future, because our minds keep on tricking us for all the right reasons, but in all different kind of ways. For now I leave you with the next example, where 'A' and 'B' again have the same color.

(so, for people who think I am quite grey: are you sure it's not just only in your mind?):-)

More from Richard Gregory:
http://www.richardgregory.org/experiments/index.htm

Want to make your own little dragon?
http://www.grand-illusions.com/opticalillusions/dragon_illusion/
http://www.pontomidia.com.br/ricardo/greatweb/gathering_for_gardner_paper_dragon.html
Not just dragons, a skeleton too:
http://ravensblight.com/Illusion.html